Triumph Repair: engine wont start continued, compression gauge, gasoline car

Question
hi howard,

I tested the compression today, and according to my gauge, 1 and 2 have 95 psi, while 3 and 4 are 30 and 60 respectively. I took multiple readings.

I changed in the new spark plugs while I had the holes open and managed to start the car with the help of some carb cleaner. I managed to get it started several times after that, but couldn't keep it running unless I applied the gas to well over 2500 rpms or pulled out the manual choke. The radiator fan and the belts seemed to be running very fast and the engine did not sound very healthy.

I'm rather lost.

Answer
Hi Will,

Either your compression gauge is defective or you didn't open the throttle while testing. Most gasoline car engines will not run with a below 100 PSI compression test. You should have at a minimum of 125 PSI on all cylinders. Most British cars test at 145 to 165 PSI.

I found it is a waste of time trying to make an engine run correctly with even one cylinder down around 100 PSI.

First find another compression gauge and run the tests again and be sure to hold the throttle open.

Howard